In reinforced concrete construction, it is necessary to support the reinforcing bars (“rebars”) in their designated locations during placement of the concrete and thereafter as it cures. This was accomplished, in its most rudimentary form, by simply resting the rebars on pieces of concrete placed on the surface. Obviously, this approach was unsatisfactory for many reasons, such as the lack of any means for fixing the rebars at their designed positions, as a result of which the rebars were displaced as the concrete was poured.
In response to the shortcomings of this method of supporting rebars, welded wire supports were developed and are used extensively in the reinforced concrete construction industry. With metal supports, however, there is a potential problem of corrosion. Coating the wire with epoxy is a method of dealing with this problem, but coating is expensive, and if the coating is damaged, corrosion may still occur. Such devices further take time to accurately be installed on site, as necessitating external connection means to securely connect reinforcing bars to the welded wire supports, resulting in high concrete construction costs.
However, plastic supports are generally non-corrodible and therefore overcome the problems noted above with welded wire supports, but they usually lack the open construction provided by wire supports that permits full flow of concrete through and around the support during concrete placement. While some patent documents disclose supports that may be formed of plastic and have openings formed in them to facilitate concrete placement, most supports are individual units as opposed to supports that may extend for several spans. Some others provide interconnectable features, however, there is still a need for improved slab bolster uppers that can easily, strongly and securely be connected one to another for their applications in concrete construction.